How have you solved the puzzle and utilizing CIAM for this purpose?  Should CIAM focus purely on authenticating/authorization the customers or having more control of contact information, consents and preferences (I'd prefer the latter one)?  

I believe that CIAM should focus on more than just authenticating and authorizing customers. It should also provide organizations with the ability to manage contact information, consents, and preferences. This is important for a number of reasons:

It allows organizations to build stronger relationships with their customers. By having a better understanding of their customers' contact information, consents, and preferences, organizations can provide more personalized and relevant experiences.
It helps organizations to comply with data privacy regulations. Many data privacy regulations, such as the GDPR and CCPA, require organizations to obtain consent from their customers before collecting and processing their personal data. CIAM can help organizations to manage this consent process effectively.
It gives organizations more control over their data. By managing contact information, consents, and preferences within CIAM, organizations can reduce their reliance on third-party systems and have more control over their data security.

By expanding CIAM to cover these aspects, you can create a more comprehensive and customer-centric approach to managing customer identities. This not only enhances security and compliance but also contributes to improved customer experiences and relationships. However, it's crucial to strike the right balance between data control and customer convenience, ensuring that customers feel empowered and in control of their data while also meeting regulatory requirements.